| Title | Multi-Stage Rubber Bearings for Seismic Isolation |
| Authors | Morikawa, Shoichi; Masaki, Nabuo; Suzuki, Shigenobu; Suizu, Youji |
| Publication | Proceedings of the International Meeting on Earthquake Protection of Buildings, Ancona, Italy, June 6-8, 1991 |
| Objectives | Demonstrate the stability of multi-stage bearings at large relative displacements and their applicability to light weight structures. |
| Abstract | In recent years, seismic isolated buildings with rubber bearings have been put to practical use in large numbers and it seems they will increase more in the future. On the other hand, apart from isolating an entire building, isolating floors or isolating frames that isolate only a part for which protection of confidential information and reduction of damage due to an earthquake (for example; computer rooms only or precision instrument parts only) are required are going to be developed. For a seismic isolator to be used for the isolating floors and the like, we come across an idea to apply rubber bearing. However, equipment load is too small (20-59kN) to apply the simply miniaturized building-use rubber without any changes, and if we attempt to materialize a seismic isolator with the rubber bearings in an ordinary structure, the rubber bearings become very long and narrow in the shape and they also become unstable. Multi-stage rubber bearings were developed to solve this problem. The multi-stage rubber bearings are the rubber bearings in such a structure that consists of small rubber bearings (rubber bearing elements) located at the four corners and stacked to multi-stage with stabilizers between each layer. Thanks to this structure, they can have great displacement absorbing capacity while maintaining horizontal stiffness equal to the very long and narrow rubber bearings. In this report, we describe the structure, the actual size model experiment result and execution examples of the seismic isolating floors that employed the multi-stage rubber bearing elements that employed the multi-stage rubber bearings in which high damping rubber bearing elements are used (multi-stage rubber bearing high damping type) as the seismic isolator. In addition, we introduce some examples of application for wooden houses and seismic isolated buildings with long natural period as other uses of the multi-stage rubber bearings. |
